Sims (2015): habitual practice, hypertension advice and causation

Sims v MacLennan

[2015] EWHC 2739 (QB)
High Court, Queen’s Bench Division
HHJ Simpkiss, sitting as a Deputy High Court Judge
Judgment delivered: 9 October 2015

Background

Mr Paul Sims underwent a medical examination on 21 November 2002 as part of the process for recovering his driving licence following a disqualification.

The defendant, Dr Neil MacLennan, was not Mr Sims’ usual GP. He undertook driving-licence and insurance examinations as a regular part of his practice.

Mr Sims’ blood pressure was recorded on the DVLA form as 182/105 mmHg, substantially above the accepted normal range.

Dr MacLennan had no specific recollection of the consultation. His evidence was based on:

• the contemporaneous DVLA form.
• his established procedure for conducting such examinations.
• his habitual practice when encountering an abnormally high blood-pressure reading.

Mr Sims did not attend his regular GP for follow-up after the examination.

In September 2007, his regular GP recorded advice to attend the practice nurse for a blood-pressure review. Mr Sims did not do so. His blood pressure was next documented in August 2011, when it was 207/102 mmHg.

Mr Sims subsequently suffered strokes and died on 7 September 2011. His widow brought proceedings on behalf of his estate and as a dependant.

Damages were agreed at £40,000, subject to liability and causation.

The allegations

The claimant alleged that Dr MacLennan had:

• failed to advise Mr Sims that his blood pressure was high and required reassessment.
• failed to tell his regular GP about the abnormal reading.
• caused Mr Sims to believe that the reading was attributable to white-coat hypertension and did not require further investigation.
• failed to document advice to seek further medical attention.

The parties’ GP experts agreed that failure to advise Mr Sims to consult his GP about the reading would have fallen below the required standard.

The primary factual question was therefore whether that advice had probably been given.

The central issues

The court considered:

1. whether Dr MacLennan advised Mr Sims to consult his GP about the raised blood pressure.
2. whether Mr Sims’ regular GP advised him in 2007 to attend for blood-pressure review.
3. whether attendance in 2002 would probably have led to a diagnosis of hypertension.
4. whether Mr Sims would have accepted medication and lifestyle advice.
5. whether earlier treatment would probably have prevented the strokes.
6. whether material-contribution principles could replace conventional but-for causation.
7. whether failure to attend in 2007 amounted to contributory negligence or broke the chain of causation.

The evidential difficulty

Neither Dr MacLennan nor Mr Sims could give direct evidence of the consultation.

Dr MacLennan had no specific recollection because the examination had taken place approximately 12 years before trial. Mr Sims had died before the proceedings.

The claimant and her sister gave evidence about conversations with Mr Sims following the examination. Both recalled that he had referred to “white-coat hypertension”. Their evidence did not reliably establish:

• the precise words used.
• whether Dr MacLennan had diagnosed white-coat hypertension.
• whether it had been presented only as a possible explanation.
• whether Mr Sims had also been advised to consult his GP.

The court therefore had to evaluate the contemporaneous document, the indirect recollections and Dr MacLennan’s evidence of habitual practice.

Habitual-practice evidence

Dr MacLennan described his usual approach to a substantially raised blood-pressure reading during a medical examination.

He would ordinarily:

• repeat the measurement.
• allow the patient to rest between readings.
• calculate or record a representative reading.
• ask about previous blood-pressure measurements and family history.
• explain that hypertension could not be diagnosed from one consultation.
• mention that anxiety or white-coat hypertension might elevate the reading.
• advise the patient to consult their regular GP for reassessment.
• explain that persistent hypertension would require treatment.

He was adamant that it would have been unthinkable for him to record a blood pressure of 182/105 without advising follow-up.

The court accepted that this usual practice had probably been followed.

White-coat hypertension

The court found that Dr MacLennan probably mentioned white-coat hypertension as a possible explanation for the high reading.

It rejected the allegation that he diagnosed the condition or told Mr Sims that no further assessment was necessary.

A diagnosis of white-coat hypertension could not properly be made from readings taken during a single examination. Dr MacLennan understood that limitation.

The court found that he probably explained both propositions:

• anxiety might account for the raised reading.
• the reading nevertheless required reassessment by Mr Sims’ regular GP.

Providing reassurance about a potentially benign explanation was not negligent because it was accompanied by clear advice that further investigation remained necessary.

Failure to act does not prove absence of advice

The claimant argued that Mr Sims would have followed advice to consult his GP and that his failure to do so supported the inference that no advice had been given.

The court rejected that reasoning.

Patients do not invariably follow medical advice, particularly where:

• they have no symptoms.
• the risk appears remote rather than immediate.
• the condition may require long-term medication.
• lifestyle changes may be recommended.
• a potentially benign explanation has been discussed.

Advice to exclude cancer or address an immediate danger may be more likely to prompt attendance than advice about an asymptomatic risk that may have consequences many years later.

Mr Sims’ failure to attend was therefore not strong evidence that the advice had not been given.

His later failure to attend for a blood-pressure review in 2007 provided some additional evidence that he was not consistently compliant with medical advice.

The documentation issue

The DVLA form recorded the blood-pressure result but not any advice given to Mr Sims.

The court held that the absence of such a note did not establish negligence.

This was a one-off examination conducted for the DVLA rather than an ordinary consultation within Mr Sims’ GP medical record. The form:

• was designed for the licensing assessment.
• offered no obvious place to record wider clinical advice.
• was not available to Mr Sims’ regular GP.
• did not operate as a continuing clinical record.
• did not itself create a duty of ongoing management.

On the facts of this case, there was no separate duty to record the advice on the DVLA form. Nor did Dr MacLennan have a duty to contact Mr Sims’ regular GP directly. It was sufficient to advise Mr Sims to arrange follow-up.

Findings on breach

The court found that Dr MacLennan:

• informed Mr Sims that his blood pressure was higher than it should have been.
• probably mentioned white-coat hypertension as a possible explanation.
• did not present white-coat hypertension as an established diagnosis.
• advised Mr Sims to consult his regular GP.
• explained that persistent hypertension might require treatment.
• took a reasonable approach supported by responsible general practice.

Accordingly, there was no breach of duty.

The 2007 advice

Mr Sims attended his regular GP in September 2007 for unrelated concerns.

The record included the entry “for PN BP rev”, meaning that he had been advised to see the practice nurse for a blood-pressure review.

The court accepted the GP’s evidence about the meaning of that entry and found that the advice had been given.

Mr Sims did not attend for the review.

No blood-pressure measurement was documented between the DVLA examination in 2002 and the markedly elevated reading in August 2011.

The causation pathway

Although the claim failed on breach, the court considered causation.

The claimant had to establish a sequence of factual propositions:

1. Mr Sims would have attended his GP if advised in 2002.
2. His blood pressure would still have been elevated.
3. Further assessment would have resulted in a diagnosis of hypertension.
4. Treatment and lifestyle advice would have been offered.
5. Mr Sims would probably have complied with that management.
6. Treatment would probably have controlled his blood pressure.
7. Adequate control would probably have prevented the strokes or materially reduced their severity.

Failure to prove an earlier link prevented progression to the later stages.

The court emphasised that medical causation could not be considered in isolation from these prior factual questions.

Whether hypertension would have been diagnosed in 2002

The 2002 measurement was taken on one occasion during an examination that Mr Sims found important and potentially anxiety-provoking.

There were several realistic possibilities:

• his blood pressure might have returned to normal after the examination.
• repeat measurements might have remained raised without resulting in a diagnosis.
• or further assessment might have confirmed hypertension.

The claimant’s GP expert considered that the blood pressure would have remained elevated. However, he could identify no scientific basis for that conclusion and ultimately described it as reflecting his experience or a “hunch”.

The court preferred the defendant expert’s evidence that the position could not reliably be determined.

The later severe hypertension in 2011 did not prove that hypertension would have been confirmed nine years earlier. Retrospective extrapolation was unsupported by evidence.

The claimant therefore failed to prove that attendance in 2002 would probably have resulted in a diagnosis of hypertension.

Compliance with treatment

The court considered that, if Mr Sims had been formally diagnosed with hypertension and placed under the management of his regular GP, he would probably have complied gradually with medication and follow-up.

His smoking, alcohol consumption and earlier non-attendance did not establish that he would have refused all treatment.

The court distinguished between:

• general advice given during a one-off medical assessment.
• an established diagnosis managed through regular GP appointments, repeat measurements and prescribed medication.

Difficulty making immediate lifestyle changes did not mean that a patient would probably reject all medical management.

Medical causation

The claimant argued that untreated hypertension either:

• probably caused the stroke under the conventional but-for test.
• made a material contribution to the stroke, allowing a modified causation test.

The court rejected both routes.

The relevant comparison was not between:

• a person with hypertension.
• a person without hypertension.

It was between:

• hypertension left untreated.
• hypertension adequately treated.

Evidence that hypertension generally doubles the risk of stroke did not establish that failure to treat Mr Sims’ assumed hypertension more than doubled his individual risk compared with successful treatment.

The expert evidence suggested that blood-pressure control might have reduced the estimated stroke risk from approximately 11% to 7%, a relative reduction of about 38%. That did not establish that the stroke would probably have been prevented.

The claimant therefore failed to prove on the balance of probabilities that earlier treatment would have prevented the stroke.

Increase in risk was insufficient

The court drew a clear distinction between:

• proving that untreated hypertension increased the risk of stroke.
• proving that untreated hypertension probably caused the particular stroke.

An increased risk, without more, does not satisfy the ordinary test of causation.

The relevant evidence did not show that treatment would have reduced the risk by more than 50% or otherwise support the conclusion that the stroke probably would not have occurred with treatment.

The evidence could not establish whether untreated hypertension caused the stroke, merely increased its risk.

Material contribution

The claimant argued that the material-contribution approach should apply because hypertension was an important factor in the development of the stroke, even if its precise contribution could not be quantified.

The court rejected that argument.

Material-contribution principles generally apply where:

• several factors cumulatively produce a divisible injury.
• tortious and non-tortious exposures act through the same injurious process.
• medical science cannot apportion the respective contributions.

The stroke was an indivisible event potentially caused by several distinct factors. This was not a cumulative dose case in which each exposure physically added to the same disease process.

The evidence showed only that untreated hypertension may have increased the risk. It did not establish that it made an actual, more-than-negligible contribution to the stroke.

The ordinary but-for test therefore remained applicable.

Contributory negligence

The contributory-negligence issue was academic because the court found no breach and no causation.

Nevertheless, the court considered what the position would have been if Dr MacLennan had negligently failed to give advice in 2002.

Mr Sims was expressly advised in 2007 to attend for a blood-pressure review but failed to do so. The court considered that omission negligent, particularly because he knew he had previously received a high reading.

However, his conduct would not have broken the chain of causation. A patient’s failure to respond to later advice was not so independent or overwhelming as to extinguish the consequences of the assumed earlier professional breach.

The court would instead have reduced damages by 25% for contributory negligence.

That apportionment reflected:

• the greater blameworthiness of a medical professional making the assumed error.
• Mr Sims’ lesser responsibility as a patient.
• his failure to attend for a specifically recommended review.
• the causative significance of that missed opportunity.

Outcome

The court held that:

• Dr MacLennan probably advised Mr Sims to consult his regular GP.
• mentioning white-coat hypertension did not negate that advice.
• failure to document the advice was not negligent in the context of the DVLA examination.
• there was no duty to contact Mr Sims’ regular GP directly.
• hypertension in 2002 was not proved.
• earlier treatment was not proved likely to prevent the strokes.
• material-contribution principles did not apply.
• the claim should be dismissed.
• had liability otherwise been established, damages would have been reduced by 25% for contributory negligence.

Significance for clinical practice

• Repeat markedly abnormal readings. A single elevated measurement should generally be confirmed appropriately.
• Avoid premature diagnosis. White-coat hypertension cannot be established from one consultation alone.
• Combine reassurance with clear action. A benign explanation may be discussed, but the need for reassessment must remain explicit.
• State what the patient must do. Advice should identify who should reassess the result and within what timescale.
• Explain the reason for follow-up. Patients should understand that persistent hypertension may require treatment.
• Document important advice where practicable. Although the claim failed despite the absence of a note, a contemporaneous record would have substantially reduced the evidential dispute.
• Do not assume compliance. A patient may fail to act even after receiving appropriate advice.
• Consider the clinical setting. Duties arising during an occupational, insurance or licensing examination may differ from those in ordinary continuing care.
• Close the communication loop where systems permit. Modern practice may justify stronger documentation and direct communication than the historical process considered here.
• Safety-net incidental findings. Clinically significant abnormalities identified during non-treatment examinations still require appropriate communication.

Significance for factual evidence

• Evidence of habitual practice may be persuasive where no specific recollection exists.
• Its weight depends upon the consistency, specificity and inherent probability of the described routine.
• The court will test habitual-practice evidence against contemporaneous documents and subsequent conduct.
• Absence of documentation is relevant but not automatically determinative.
• A patient’s failure to follow advice does not establish that the advice was not given.
• Indirect recollections reported many years later must be treated cautiously.
• Memorable phrases may be recalled accurately while the surrounding advice is forgotten.
• A clinician’s confidence that advice would always have been given requires scrutiny but may still be accepted.

Significance for causation

• Establish each step in the hypothetical pathway separately.
• Do not infer an earlier diagnosis solely from a later abnormal result.
• Distinguish untreated hypertension from hypertension itself when assessing relative risk.
• Identify the correct comparator: treated versus untreated disease.
• A risk increase does not automatically prove individual causation.
• Epidemiological evidence must answer the specific counterfactual question in the case.
• Material contribution is not a general substitute where but-for causation is difficult to prove.
• Distinguish cumulative divisible injury from an indivisible event with several possible causes.
• Expert intuition or clinical experience cannot replace an identifiable evidential basis for a probabilistic conclusion.

Practical framework for an incidental high blood-pressure reading

When a materially raised blood pressure is identified during a one-off assessment:

1. confirm the technique and cuff size.
2. repeat the measurement after appropriate rest.
3. record the relevant readings.
4. ask about previous blood-pressure measurements.
5. consider symptoms requiring urgent assessment.
6. consider possible situational elevation without diagnosing it prematurely.
7. explain that one consultation cannot confirm or exclude hypertension.
8. tell the patient clearly that reassessment is required.
9. identify who should perform that reassessment.
10. specify an appropriate timescale.
11. explain the possible significance of persistent hypertension.
12. record the advice given.
13. provide written instructions where practical.
14. consider whether direct communication with the patient’s usual clinician is necessary.

Educational case commentary only. It is not legal or medical advice and is not a substitute for the full judgment. The publication date above is the date of this commentary, judgment was delivered on 9 October 2015.